Startup control for a high pressure discharge lamp ballast
US8324829B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 26, 2010 |
| Grant date | Dec 4, 2012 |
| Priority date | — |
| Expiry date | Nov 2, 2030 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A high pressure discharge lamp ballast is provided with a control operation for stable transition from a lamp ignition mode into a preheating mode. An inverter is coupled across a DC source and has a plurality of switching elements coupled to the high pressure discharge lamp. A series resonant LC circuit is coupled to the inverter outputs and to the high pressure discharge lamp. A control circuit is coupled to the switching elements and configured to control switching operation. An ignition mode has one or more time periods during each of which a driving frequency of the switching elements is swept through a predetermined range of frequencies and then controlled at a first driving frequency less than the predetermined range of frequencies. A preheating mode follows wherein the switching elements are controlled at a second driving frequency less than the predetermined range of frequencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.